Method Of Detection For An Over-Loaded Drying Capacity In A Clothes Dryer Or A Combo Washer-Dryer Dryer

ABSTRACT

A method of controlling load volume in a laundry drying appliance where a load of wet laundry is place in a drum of the laundry drying appliance and the load volume of the wet laundry is sensed or determined according to the method. A condition of the drum of the laundry drying appliance is actively monitored and a determination is made if a proper load volume is present in laundry drying appliance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application Claims the Benefit of U.S. Provisional Application No. 63/274,987, filed on Nov. 3, 2021. The entire disclosure of the above application is incorporated herein by reference.

FIELD

The present disclosure relates to a device and method of controlling load volume in a laundry appliance such as dryer or combination washer/dryer appliance.

BACKGROUND

When washing and drying clothes in either a washer/dryer pair or a single combination washer/dryer appliance, it is desirable to have the clothes as wrinkle fee as possible after drying has taken place. The biggest problem with drying clothes is the size of the wet load volume, added to the dryer. If a proper amount of wet clothes is added into the dryer, drying will occur, with the clothes experiencing a limited amount of wrinkles. If the dryer is overloaded with wet clothing, the clothing, after drying, ends up very wrinkled. Especially in a washer/dryer combination, where only one drum exists, it is particularly important to ensure that the wet clothes volume load is proper.

Generally, in a washer/dryer pair, the dryer capacity is larger than the washer capacity. This is an attempt to provide a wet clothes load volume that is proper to add into the dryer. During drying, the clothes are tumbled. As the clothes dry, they expand in the drum. This reduces the airflow in the drum which, in turn, reduces performance. Accordingly, if the dryer is overloaded with a wet load volume, the clothing will end up very wrinkled.

In a washer/dryer combo, only one drum is present. Thus, it is of utmost importance that the drum is not overloaded during the washing cycle. Thus, proper airflow can be achieved and moved through the drum to provide optimum drying performance. Thus, it is important for the drum to be loaded at 50-60% capacity in order to provide a proper drying without the clothes ending up wrinkled.

Accordingly, it is an object of the present disclosure to overcome the disadvantages of the prior art. The present disclosure provides a device and method of controlling the load volume of items or clothes loaded into a drying appliance. Specifically, the west load volume positioned within the drum of the drying appliance is monitored.

SUMMARY

According to an object of the present disclosure, a method of controlling a wet load volume loaded into a drying appliance comprises determining a volume of wet items to be positioned into the drying appliance. The wet items are positioned into the drying appliance. The volume of wet items in the drying appliance are sensed. The volume of wet items in the drying appliance is determined. A condition of the drum of the drying appliance is actively monitored. A proper volume of clothes is determined to be present in the drum of the drying appliance. The drying cycle is terminated if a proper volume of items in the drum is exceeded. Airflow, pressure drop or evaporation rate may be monitored in the drum during operation to determine if a proper load volume is present in the drum. Power draw on a fan motor associated with providing airflow to the drum during operation may be monitored to determine the proper load volume. Additionally, monitoring of sound within the drum to detect sound variation of the volume of items in the drum during operation may occur. Motor torque signal monitoring of the drum motor may occur during operation to determine the volume of items within the drum.

According to another aspect of the disclosure, a method of controlling a load volume of laundry in a laundry drying appliance is provided. The method includes the steps of: sensing a condition of the laundry drying appliance that is indicative of the load volume of laundry in the laundry drying appliance by receiving and processing one or more electrical signals from one or more sensors or electrical components positioned within the laundry drying appliance; determining the load volume of laundry in the laundry drying appliance based on the condition of the laundry drying appliance that is indicative of load volume; and determining if the load volume of laundry present in the laundry drying appliance exceeds a pre-determined maximum load volume value for a particular drying cycle of the laundry drying appliance.

The displacement of the drum during loading may be monitored to determine the load volume added into the drum. Image sensing of the items position into the drying appliance may be utilized to determine the load volume in the drum. A basket volume with items, may be sensed outside of the drum to estimate the load volume prior to entering the drum. A basket with a proper load volume may be provided within the drum.

According to another aspect of the disclosure, a drying appliance comprises a cabinet with an opening enabling access inside the cabinet. A door is coupled with the cabinet. The door covers the opening. A heating unit is provided inside of the cabinet and a drum receives items to be dried in the drying appliance. The drum is expandable and retractable to provide a desired volume in the drum. The drying appliance is a combination washing/drying machine. The drum has a smaller volume during washing and expands to have a larger volume during drying.

In accordance with another aspect of the present disclosure, a laundry drying appliance is provided, comprising: a cabinet with an opening enabling access inside the cabinet; a door coupled with the cabinet, the door covering the opening; a heating unit configured to heat air inside of the cabinet; a drum configured to receive laundry to be dried in the drying appliance; a control panel with a user interface that is configured to permit user selection of a desired drying cycle; and a controller integrated with or arranged in electronic communication with the control panel.

The controller is programmed to: (1) process one or more electrical signals that are received from one or more sensors or electrical components positioned within the cabinet to detect a condition of the laundry drying appliance that is indicative of load volume, (2) determine the load volume of laundry in the drum based on the condition of the laundry drying appliance that is indicative of load volume, and (3) determine if the load volume of laundry present in the drum exceeds a pre-determined maximum load volume value for the desired drying cycle.

According to another aspect of the disclosure, a drying appliance comprises a cabinet with an opening enabling access inside the cabinet. A door is coupled with the cabinet to cover the opening. A heating unit provides heat inside of the cabinet and a drum receives items to be dried in the drying appliance. A basket is in the drum for receiving a load volume of items. The basket is removable from the drum. The basket provides a proper amount of items, load volume, to be dried by the drying appliance. The basket can be rigid or flexible. The drying appliance is a combination washer/dryer.

In accordance with another aspect of the present disclosure, a washer/dryer combination appliance is provided, comprising: a cabinet with an opening enabling access inside the cabinet; a door coupled with the cabinet, the door covering the opening; a heating unit configured heat air inside of the cabinet; a tub suspended within the cabinet; a drum rotatably supported within the tub, the drum configured to receive laundry to be washed and dried in the washer/dryer combination appliance; a control panel with a user interface that is configured to permit user selection of a desired drying cycle; and a controller integrated with or arranged in electronic communication with the control panel.

The controller is programmed to: (1) process one or more electrical signals that are received from one or more sensors or electrical components positioned within the cabinet to detect a condition of the laundry drying appliance that is indicative of load volume, (2) determine the load volume of laundry in the drum based on the condition of the laundry drying appliance that is indicative of load volume, and (3) determine if the load volume of laundry present in the drum exceeds a pre-determined maximum load volume value for the desired drying cycle.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a front perspective view of an exemplary laundry appliance;

FIG. 2 is a schematic diagram showing a side cross-section view of an exemplary dryer;

FIG. 3 is a schematic diagram showing a side cross-section view of an exemplary combination washer/dryer appliance;

FIG. 4 is a schematic diagram showing a side cross-section view of another exemplary combination washer/dryer appliance;

FIG. 5 is a front perspective view of an exemplary drum for a laundry drying appliance;

FIG. 6 is a flow diagram of an exemplary method for determining load size and an over loaded condition in the drum based on motor torque;

FIG. 7A is a plot illustrating motor torque and rotational speed curves for different load sizes of laundry in the drum at a ramp rate of 5 RPMs per second;

FIG. 7B is a plot illustrating other motor torque and rotational speed curves for different load sizes of laundry in the drum where the ramp rate is 10 RPMs per second;

FIG. 7C is a plot illustrating other motor torque and rotational speed curves for different load sizes of laundry in the drum where the ramp rate is 15 RPMs per second;

FIG. 7D is a plot illustrating other motor torque and rotational speed curves for different load sizes of laundry in the drum where the ramp rate is 20 RPMs per second;

FIG. 7E is a plot illustrating other motor torque and rotational speed curves for different load sizes of laundry in the drum where the ramp rate is 25 RPMs per second;

FIG. 8 is a flow diagram of an exemplary method for determining load size in the drum based on the output of weight sensors located in the dampers;

FIG. 9 is a plot illustrating a calibration curve for different load sizes of laundry in the drum;

FIG. 10 is a flow diagram of an exemplary method for determining load size and a flow obstruction condition in the drum based on exhaust temperature;

FIG. 11 is a plot illustrating exhaust temperature and time curves for different load sizes of laundry in the drum and different airflow conditions;

FIG. 12 is a flow diagram of an exemplary method for determining load size in the drum based on evaporation rate;

FIG. 13 is a plot illustrating evaporation rate and time curves for different load sizes of laundry in the drum and different airflow conditions;

FIG. 14 is a flow diagram of an exemplary method for determining load size and an overload condition in the drum based on the output of force sensors located in the drum;

FIG. 15A is a plot illustrating a force and time curve for a small load size of laundry in the drum;

FIG. 15B is a plot illustrating a force and time curve for a medium load size of laundry in the drum; and

FIG. 15C is a plot illustrating a force and time curve for a large load size of laundry in the drum.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

Turning to the figures, a laundry drying appliance is illustrated and designated with the reference numeral 10. The laundry drying appliance 10 includes a cabinet 12 and a door 14 to enable access inside the cabinet 12. A control panel 16 is present on the cabinet 12 for providing a user interface. A drum 20 is positioned inside of the cabinet 12 to receive a load volume of laundry to be dried. The laundry drying appliance 10 that is illustrated in FIGS. 1 and 2 is a dryer only and includes a controller 22 for controlling the various cycles, components and the like of the laundry drying appliance 10.

With reference to FIG. 2 , the laundry drying appliance 10 also includes a heater 24, which heats air within the cabinet 12 before it passes through holes or apertures in the drum 20 to heat the load volume of laundry within the drum 20. The drum 20 includes baffles or lifters 26 to assist in lifting or moving the laundry in the drum during tumbling operations. A drum motor 28 positioned inside the cabinet 12 is coupled to and rotates the drum 20. An exhaust system 30 includes a lint screen 32 within an exhaust duct 34. The exhaust duct 34 also includes a fan 36 and an exhaust outlet 38. The fan 36 pulls air in and through the entire exhaust system 30 so that lint can be caught in the lint screen 32 and air can be blown out through the exhaust outlet 38.

Various types of sensors 40 a-40 i may be positioned throughout the laundry drying appliance 10 to monitor the load volume of wet laundry positioned in the drum 20. The sensors 40 a-40 i are electronically coupled with the controller 22 to enable the determination that a proper load volume of wet laundry is positioned in the drum 20. The sensors 40 a-40 i actively monitor the condition of the laundry drying appliance 10 before and during operation. Sensors 40 c, 40 f, 40 g may detect the airflow, pressure drop or evaporation rate of the airflow within the drum 20 during operation to, in turn, determine proper load volume. Additionally, the sensor 40 c may monitor the power draw of the fan 36 associated with the exhaust system 30 during operation to, in turn, determine proper load volume. The sensor 40 a may monitor the sound within the drum 20 to detect sound variation of the load volume of laundry tumbling within the drum 20 during operation to, in turn, determine the proper load volume. For example, the sound of laundry tumbling within the drum 20 may have a higher frequency when the drum 20 is has a large load volume compared to a small load volume, such that the frequency of the sound coming from the drum 20 can be processed to estimate the load size. Additionally, the sensor 40 b may monitor the motor torque signal of the drum motor 28 during operation to, in turn, determine proper load volume. Further, sensors 40 h, 40 i may monitor the displacement of the drum 20 during loading of the drum 20 with the load volume of laundry to, in turn, determine proper load volume.

Additionally, an image sensor 50 may be present in the laundry appliance 10. The image sensor 50 may sense individual items of laundry as they are added into the drum 20. As shown in FIG. 2 , the image sensor 50 may also sense a basket 52 positioned in front of the laundry drying appliance 10. The image sensor 50 may estimate the load volume of the laundry contained in the basket 52 to, in turn, determine proper load volume. As shown in FIG. 4 , the image sensor 50 may alternatively be positioned with a line of sight pointing towards a rear wall 21 of the drum 20. The drum 20 may be made of metal such that the rear wall 21 of the drum 20 is shiny and therefore has high optical contrast compared to a typical load of laundry. The image sensor 50 may be used to image/detect a bright area or number of bright pixels associated with the drum 20 or rear wall 21 when the drum 20 is empty. The image sensor 50 may then be used to image/detect the bright area or number of bright pixels associated with the drum 20 or rear wall 21 when the drum 20 is loaded. Because the laundry in the drum 20 will obstruct/cover some of the bright area or number of bright pixels associated with the drum 20 or rear wall 21, the load size can be estimated based on the percentage change in the bright area/number of bright pixels. The controller 22 may be configured to display an overload warning on the control panel 16 if the change in the bright area/number of bright pixels detected by the image sensor 50 during loading exceeds a predetermined threshold. For example, the predetermined threshold may be when ⅝ or more of the detected bright area or number of bright pixels become obscured.

Additionally, a basket 52 having a proper load volume for laundry to be positioned within the laundry drying appliance 10 may be included with and removable from the laundry drying appliance 10. The amount of laundry would be first placed into the basket 52 and then into the drum 20 to provide the proper volume load in the drum 20.

Additionally, sensors 40 d, 40 e may be present in the baffle or lifter 26 to determine the amount of force exerted on the baffle or lifter 26 during operation to, in turn, determine the proper load volume.

The laundry drying appliance illustrated in FIG. 3 is a combination washer/dryer appliance 10′. Thus, it should be appreciated that the laundry drying appliance may perform drying cycles only, such as the case with the laundry drying appliance 10 illustrated in FIGS. 1 and 2 , or may perform both washing and drying cycles, like the combination washer/dryer appliance 10′ illustrated in FIG. 3 . The items identified above in connection with the laundry drying appliance 10 that perform a similar function in the combination washer/dryer 10′ are designated with the same reference numerals.

The washer/dryer combination appliance 10′ includes a tub 60 that is positioned about the drum 20. The tub 60 is suspended inside the cabinet 12. The drum 20 rotates within the tub 60, but the tub 60 does not rotate within the cabinet 12. A pump 62 is positioned inside the cabinet 12 below the drum 20 and is configured to recycle/recirculate water within the tub 60 and, in turn, drum 20. Sensors 40 a-40 i and image sensor 50 are contained within the washer/dryer combination appliance 10′ like in the laundry drying appliance 10 as previously discussed.

Optionally, a basket 70 may be positioned within the washer/dryer combination appliance 10′. The basket 70 may be secured with the lifters 26 on the drum 20. The basket 70 may be flexible or rigid. Thus, a load volume of laundry would be placed in the basket 70. The laundry would be washed and dried in a single cycle. Additionally, the image sensor 50 could be utilized to sense that the basket 70 is full with a proper load volume. An interface with the user, via the control panel, would indicate that a proper load volume is ready to be positioned into the drum 20.

The laundry drying appliance illustrated in FIG. 4 is a combination washer/dryer appliance 10″, which may perform both washing and drying cycles, like the combination washer/dryer appliance 10′ illustrated in FIG. 3 . The items identified above in connection with the combination washer/dryer appliance 10′ that perform a similar function in the combination washer/dryer 10″ are designated with the same reference numerals.

The washer/dryer combination appliance 10″ includes a tub 60 that is positioned about the drum 20. The tub 60 is suspended inside the cabinet 12 by a combination of biasing members 72 (e.g., springs) and dampers 74. The tub 60, biasing members 72, and dampers 74 form a spring-mass-damper system that permits the tub 60 to move and oscillate to a limited degree within the cabinet 12. Thus, the drum 20 rotates within the tub 60, but the tub 60 does not rotate within the cabinet 12. A pump 62 is positioned inside the cabinet 12 below the drum 20 and is configured to recycle/recirculate water within the tub 60 and, in turn, drum 20. Sensors 40 a-l and image sensor 50 are contained within the washer/dryer combination appliance 10″ like in the combination washer/dryer appliance 10′ as previously discussed. However, the washer/dryer combination appliance 10″ illustrated in FIG. 4 is different in that it does not include the optional basket 70 shown in FIG. 3 .

FIG. 5 illustrates an expandable drum 20′. The drum 20′ may include moveable panels 80 to enable the drum 20′ to expand and retract. In a combination washer/dryer appliance 10′, the drum 20′ would be arranged in a smaller volume configuration during the washing cycle. The drum 20′ would then expand to a larger volume configuration before or during the drying cycle to provide the desired load volume for washing and, in turn, the desired load volume for drying. Additionally, the expandable and retractable drum 20′ could be utilized in a drying only laundry appliance (i.e., a dryer). Here, the drum 20′ would be arranged in the smaller volume configuration before the drying cycle commence when a user places the wet load volume of laundry into the drum 20′. Upon activation of the drying cycle, the drum 20′ would expand to provide a proper volume size for the drum for drying purposes.

The image sensor 50 may detect the number or size of the items of laundry positioned in the drum 20 and provide a user with a signal that the drum 20 was at a proper load volume level or is overloaded. Alternatively, the image sensor 50 could view the basket 52 and indicate that the basket 52 is at a proper load volume for the drum and/or has oversized dimensions.

The volume of wet laundry in the drum 20 may be actively monitored during operation of the laundry appliance 10. Sensors 40 c, 40 f, 40 g may continuously or periodically monitor the airflow, pressure drop, and/or evaporation rate in the drum 20 and any or all of this information may be utilized to determine if a proper load volume is present in the drum 20. If a proper load is not present, then the user would be notified, via a user interface on the control panel 16, to choose another cycle or to remove some of the laundry from the drum 20. Thus, the user would be going through a learned behavior as to the proper amount of laundry to be added into the laundry appliance 10 to provide optimal drying of the items with minimal wrinkling.

Additionally, sensor 40 c could monitor the power draw of the fan motor to determine the load volume. Likewise, sensors 40 a could monitor the sound within the drum 20 to detect sound variation of the load volume to determine if a proper load is present.

Sensors 40 b could monitor the motor torque signal of the drum motor 28 during operation to determine if a proper load is positioned within the drum 20. Additionally, drum displacement could be monitored during loading by sensors 40 h and 40 i, which could be optical sensors or nearfield magnetic sensors configured to measure the position of the drum 20 or may be displacement sensors mounted in or on the dampers 74. The displacement of the drum 20 would determine if a proper load volume is present and if this amount is exceeded, a signal would be transmitted to the user.

Thus, various sensed characteristics prior to the operation of the drying appliance as well as actively monitoring characteristics during operation can be utilized to determine if a proper load volume has been positioned within the drum 20. Thus, the operation of the laundry appliance 10 is carried out with the goal of providing optimal clothes drying as well as the least amount of wrinkling during the drying process.

The present disclosure provides several exemplary methods of controlling the load volume of laundry in the laundry drying appliances 10, 10′, 10″ described above. All of these exemplary methods generally follow the following steps or routine. The routine begins with the step of sensing a condition of the laundry drying appliance 10, 10′, 10″ that is indicative of the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ by receiving and processing one or more electrical signals from one or more sensors 40, 50 or electrical components, such as the drum motor 28 or fan 36, which are all positioned within the laundry drying appliance 10, 10′, 10″. The method proceeds with the step of determining the load volume of laundry in the laundry drying appliance 10, 10′, 10″ based on the condition of the laundry drying appliance 10, 10′, 10″ that is indicative of load volume. The method then performs the step of determining if the load volume of laundry present in the laundry drying appliance 10, 10′, 10″ exceeds a pre-determined maximum load volume value for a particular drying cycle of the laundry drying appliance. The pre-determined maximum load volume may be stored in memory, such as the memory of the control panel 16 or separate controller 22, and the particular drying cycle that is considered may be any one of the drying cycles programmed into the memory of the control panel 16 or controller 22, and the particular drying cycle that has been selected by a user via the control panel 16.

One exemplary method of controlling the load volume of laundry in the drum 20 of a laundry drying appliance 10, 10′, 10″ is shown in FIG. 6 , which is a flow diagram of an exemplary method for determining load size and an over loaded condition in the drum 20, 20′ based on motor torque. The motor torque may be obtained from the drum motor 28 directly or sensor 40 b by processing one or more signals generated by the drum motor 28 of sensor 40 b, which are indicative of current draw of the drum motor 28 and motor speed (i.e., RPMs). The method begins with step 100 of powering on the laundry drying appliance 10, 10′, 10″ and progressively/gradually ramping up the rotational speed of the drum 20, 20′. The method then proceeds to step 102 of checking/measuring/monitoring the motor torque between 400 and 500 revolutions per minute (RPMs). In accordance with step 102, a measured motor torque value Tq is obtained by receiving and processing one or more signals generated by the drum motor 28 of sensor 40 b which are indicative of current draw of the drum motor 28 and/or motor speed (i.e., RPMs). The method continues with step 104 of comparing the measured motor torque value Tq obtained at step 102 to one or more motor torque benchmark values Tq0-Tq3. The motor torque benchmark values Tq0-Tq3 are predetermined values that are set by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ and will therefore vary from one appliance to another. In the illustrated example, the motor torque benchmark values Tq0-Tq3 include a motor torque benchmark value Tq0 that corresponds with an overload condition (where effective drying cannot occur or where effective drying cannot occur without excessive wrinkling), a motor torque benchmark value Tq1 value that corresponds with a large load condition, a motor torque benchmark value Tq2 value that corresponds with a medium load condition, and a motor torque benchmark value Tq3 value that corresponds with a small load condition. By determining whether the measured motor torque value Tq is greater than the various motor torque benchmark values Tq0-Tq3, the method determines at step 106 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ is too large for the laundry drying appliance 10, 10′, 10″ (i.e, an overloaded condition) or corresponds to a large load, a medium load, or a small load. The method may include triggering an overload warning at step 109 if an overload condition is determined at step 106. The overload warning may be displayed to a user on the control panel 16 and/or may disable all or some drying cycles, making them unavailable until the load size is reduced. The method may also include highlighting and/or enabling a recommended cycle setting on the control panel 16 at step 110.

An exemplary testing process for determining the motor torque benchmark values Tq0-Tq3 by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ is shown in FIGS. 7A-7E, which are a series of plots illustrating motor torque and rotational speed curves for different load sizes of laundry in the drum. In FIGS. 7A-7E, motor torque in Newton meters (Nm) is shown on the vertical y-axis and rotational speed in revolutions per minute (RPMs) is shown on the horizontal x-axis. The various curves correspond to 0, 5, 10, 15, 20, and 25 kilogram (kg) loads of laundry, where the heavier load sizes correspond to higher motor torque values. In FIG. 7A, the rotational speed of the drum 20, 20′ was increased at a ramp rate of 5 RPMs per second. The testing shows that at the 5 RPMs per second ramp rate, the resolution between the various load size curves is small (i.e., they are close together and/or overlap at some rotational speeds). In FIG. 7B, the rotational speed of the drum 20, 20′ was increased at a ramp rate of 10 RPMs per second. In FIG. 7C, the rotational speed of the drum 20, 20′ was increased at a ramp rate of 15 RPMs per second. In FIG. 7D, the rotational speed of the drum 20, 20′ was increased at a ramp rate of 20 RPMs per second. Finally, in FIG. 7E, the rotational speed of the drum 20, 20′ was increased at a ramp rate of 25 RPMs per second. These plots show that for the particular laundry drying appliance 10, 10′, 10″ that was tested, the resolution between the motor torque and rotational speed curves generally improves as the ramp rate is increased, but that some hysteresis starts occurring at high rotational speeds (between 800 and 1000 RPMs) and a ramp rate of 25 RPMs per second (FIG. 7E). Therefore, it was determined that the motor torque benchmark values Tq0-Tq3 for this particular laundry drying appliance 10, 10′, 10″ should be set at a rotational speed between 400 to 500 RPMs and a ramp rate of 15 RPMs per second (FIG. 7C).

Another exemplary method of controlling the load volume of laundry in the drum 20 of a laundry drying appliance 10, 10′, 10″ is shown in FIG. 8 , which is a flow diagram of an exemplary method for determining load size in the drum 20, 20′ based on the output of weight or displacement sensors 40 h, 40 i located in the dampers 74. The method begins with step 200 of powering on the laundry drying appliance 10, 10′, 10″ and placing (i.e., loading) laundry into the drum 20, 20′. The method then proceeds to step 202 of checking/measuring/monitoring the weight (i.e., force) applied to the dampers 74 and/or the amount of displacement of the dampers 74. In accordance with step 202 a weight/displacement value W indicating the weight and/or displacement measured at the dampers 74 is obtained by receiving and processing one or more signals generated by sensors 40 h, 40 i, which are indicative of the weight/force applied to the dampers 74 or the displacement/travel of the dampers 74 experienced during loading. The method continues with step 204 of comparing the measured weight/displacement value W obtained at step 202 to one or more motor weight/displacement benchmark values W1-W3. The weight/displacement benchmark values W1-W3 are predetermined values that are set by a calibration curve that is generated by testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ and will therefore vary from one appliance to another. In the illustrated example, the weight/displacement benchmark values W1-W3 include a weight/displacement benchmark value W1 that corresponds with a large load condition, a weight/displacement benchmark value W2 value that corresponds with a medium load condition, and a weight/displacement benchmark value W3 value that corresponds with a small load condition. By determining whether the measured weight/displacement value W is greater than the various weight/displacement benchmark values W1-W3, the method determines at step 206 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ corresponds to a large load, a medium load, or a small load. The method may also include highlighting and/or enabling a recommended cycle setting on the control panel 16 at step 208.

An exemplary testing process for determining the weight/displacement benchmark values W1-W3 by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ is shown in FIG. 9 , which is a plot illustrating a calibration curve for different load sizes of laundry in the drum 20, 20′. In FIG. 9 , sensed weight in kilograms (kg) is shown on the vertical y-axis and actual weight in kilograms (kg) is shown on the horizontal x-axis. The various data points on the plot correspond to various loads of pre-weighed laundry ranging from 0 to 8 kilograms (kg). This curve is then used to calibrate the readings/measurements obtained from the sensors 40 h, 40 i located on or in the dampers 74.

Another exemplary method of controlling the load volume of laundry in the drum 20 of a laundry drying appliance 10, 10′, 10″ is shown in FIG. 10 , which is a flow diagram of an exemplary method for determining load size and a flow obstruction condition in the drum 20, 20′ based on exhaust temperatures, which may be obtained from temperature sensor 40 g. The method begins with step 300 of powering on the laundry drying appliance 10, 10′, 10″ and initiating a drying cycle. The method then proceeds to step 302 of checking/measuring/monitoring the exhaust temperature after a pre-determined time interval. The duration of the pre-determined time interval is selected based on testing, which is explained in greater detail below. In accordance with step 302, a measured exhaust temperature value T is obtained by receiving and processing one or more signals generated by the temperature sensor 40 g, which are indicative of the exhaust temperature at the outlet of the exhaust duct 34. The method continues with step 304 of comparing the measured exhaust temperate value T obtained at step 302 to one or more exhaust temperature benchmark values T1-T4. The exhaust temperature benchmark values T1-T4 are predetermined values that are set by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ and will therefore vary from one appliance to another. The exhaust temperature benchmark values T1-T4 are stored in the memory of the control panel 16 or controller 22, in a look-up data table 316. In the illustrated example, the exhaust temperature benchmark values T1-T4 include an exhaust temperature benchmark value T1 that corresponds with an overload condition (where effective drying cannot occur or where effective drying cannot occur without excessive wrinkling), an exhaust temperature benchmark value T2 that corresponds with a large load condition, an exhaust temperature benchmark value T3 that corresponds with a medium load condition, and an exhaust temperature benchmark value T4 that corresponds with a small load condition. By determining whether the measured exhaust temperature value T is greater than exhaust temperature benchmark value T1, the method determines at step 306 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ is too large for the laundry drying appliance 10, 10′, 10″ (i.e, an overloaded condition). By determining whether the measured exhaust temperature value T is greater than exhaust temperature benchmark values T2-T4, the method determines at step 308 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ corresponds to a large load, a medium load, or a small load. The method may include stopping/terminating the drying cycle at step 310 if an overload condition is determined at step 306. The method may further include displaying an overload or service fault code to a user on the control panel 16 if an overload condition is determined at step 306. The method may also include step 314 of determining whether the user has selected a proper drying cycle on the control panel 16 for the load volume in the drum 20, 20′. If it is determined that an improper drying cycle for the load volume has been selected, the method may include the step of terminating the cycle, displaying a warning to the user on the control panel 16, or autonomously changing the drying cycle to a proper drying cycle for the load volume determined at step 308.

An exemplary testing process for determining the exhaust temperature benchmark values T1-T4 by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ is shown in FIG. 11 , which is a plot illustrating exhaust temperature and time curves for different load sizes of laundry in the drum and different airflow conditions. In FIG. 11 , exhaust temperature in degrees Celsius (° C.) is shown on the vertical y-axis and time in seconds (s) is shown on the horizontal x-axis. The various curves correspond to 1, 4, and 8 kilogram (kg) loads of laundry at high and low airflows, with and without the presence of a bypass seal that prevent air from traveling along a bypass flow path in the space between the drum 20, 20′ and the tub 60. The resolution between the various load size curves is good after about 180 seconds. After about 350 seconds some hysteresis starts occurring at some load sizes. Therefore, it was determined that the exhaust temperate benchmark values T1-T4 for this particular laundry drying appliance 10, 10′, 10″ should be set at a predetermined time interval of 180 seconds.

Another exemplary method of controlling the load volume of laundry in the drum 20 of a laundry drying appliance 10, 10′, 10″ is shown in FIG. 12 , which is a flow diagram of an exemplary method for determining load size in the drum 20, 20′ based on evaporation rate, which may be obtained from combined temperature and humidity sensors 40 f, 40 g and the inlet and outlet of the exhaust duct 38. However, it should also be appreciated that separate temperature and humidity sensors may be used. The method begins with step 400 of powering on the laundry drying appliance 10, 10′, 10″ and initiating a drying cycle. The method then proceeds to step 402 of checking/measuring/monitoring an evaporation rate (g_dot) after a pre-determined time interval. The duration of the pre-determined time interval is selected based on testing, which is explained in greater detail below. In accordance with step 402, the evaporation rate (g_dot) is obtained by receiving and processing one or more signals generated by the combined temperature and humidity sensors 40 f, 40 g, which are indicative of the exhaust temperature and humidity at the inlet and outlet of the exhaust duct 34, and then using those values to calculate the evaporation rate (g_dot) at step 404. The evaporation rate (g_dot) is calculated by multiplying the estimated mass flow rate in kilograms per second (kg/s) by the relative humidity ratio between the inlet and outlet of the exhaust duct 34. The mass flow rate may be estimated based on the rotational speed of the fan 36. The relative humidity ratio is calculated by subtracting the measured humidity ratio at the outlet of the exhaust duct 34 from the measured humidity ratio at the inlet of the exhaust duct 34. Once the evaporation rate (g_dot) is calculated from these values, the method continues with step 404 of comparing the calculated evaporation rate (g_dot) obtained at step 402 to one or more evaporation rate benchmark values g_dot1-g_dot3. The evaporation rate benchmark values g_dot1-g_dot3 are predetermined values that are set by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ and will therefore vary from one appliance to another. The evaporation rate benchmark values g_dot1-g_dot3 are stored in the memory of the control panel 16 or controller 22, in a look-up data table 412. In the illustrated example, the evaporation rate benchmark values g_dot1-g_dot3 include an evaporation rate benchmark value g_dot1 that corresponds with a large load condition, an evaporation rate benchmark value g_dot2 that corresponds with a medium load condition, and an evaporation rate benchmark value g_dot3 that corresponds with a small load condition. By determining whether the calculated evaporation rate g_dot1 is greater than the evaporation rate benchmark values g_dot1-g_dot3, the method determines at step 406 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ corresponds to a large load, a medium load, or a small load. The method may also include step 410 of determining whether the user has selected a proper drying cycle on the control panel 16 for the load volume in the drum 20, 20′. If it is determined that an improper drying cycle for the load volume has been selected, the method may include the step of terminating the cycle, displaying a warning to the user on the control panel 16, or autonomously changing the drying cycle to a proper drying cycle for the load volume determined at step 408.

An exemplary testing process for determining the evaporation rate benchmark values g_dot1-g_dot3 by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ is shown in FIG. 13 , which is a plot illustrating evaporation rate and time curves for different load sizes of laundry in the drum 20, 20′ and different airflow conditions. In FIG. 13 , evaporation rate in grams of water per minute (g/min) is shown on the vertical y-axis and time in seconds (s) is shown on the horizontal x-axis. The various curves correspond to 1, 4, and 8 kilogram (kg) loads of laundry at high and low airflows, with and without the presence of a bypass seal that prevent air from traveling along a bypass flow path in the space between the drum 20, 20′ and the tub 60. The resolution between the various load size curves is good after about 180 seconds. After about 300 seconds some hysteresis starts occurring at some load sizes. Therefore, it was determined that the evaporation rate benchmark values g_dot1-g_dot3 for this particular laundry drying appliance 10, 10′, 10″ should be set at a predetermined time interval of 180 seconds.

Another exemplary method of controlling the load volume of laundry in the drum 20 of a laundry drying appliance 10, 10′, 10″ is shown in FIG. 14 , which is a flow diagram of an exemplary method for determining load size and an overload condition in the drum 20, 20′ based on the output of force sensors 40 d, 40 e located in the drum 20, 20′. The method begins with step 500 of powering on the laundry drying appliance 10, 10′, 10″ and initiating a tumbling cycle by rotating the drum 20, 20′. The method then proceeds to step 502 of checking/measuring/monitoring the force exerted on one or more lifters 26 in the drum 20, 20′. In accordance with step 502, a measured force value F is obtained by receiving and processing one or more signals generated by the force sensor 40 d, 40 e, which are indicative of the force exerted on the lifters 26 by the laundry in the drum 20, 20′ during tumbling. The method continues with step 504 of comparing the measured force value F obtained at step 502 to one or more benchmark force values F1-F4. The benchmark force values F1-F4 are predetermined values that are set by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ and will therefore vary from one appliance to another. In the illustrated example, the benchmark force values F1-F4 include a benchmark force value F1 that corresponds with an overload condition (where effective drying cannot occur or where effective drying cannot occur without excessive wrinkling), a benchmark force value F2 that corresponds with a large load condition, a benchmark force value F3 that corresponds with a medium load condition, and a benchmark force value F4 that corresponds with a small load condition. By determining whether the measured force value F is greater than the various benchmark force values F1-F4, the method determines at step 506 whether the load volume of laundry in the drum 20, 20′ of the laundry drying appliance 10, 10′, 10″ is too large for the laundry drying appliance 10, 10′, 10″ (i.e, an overloaded condition) or corresponds to a large load, a medium load, or a small load. The method may include triggering an overload warning at step 508 if an overload condition is determined at step 506. The overload warning may be displayed to a user on the control panel 16 and/or may disable all or some drying cycles, making them unavailable until the load size is reduced. The method may also include highlighting and/or enabling a recommended cycle setting on the control panel 16 at step 510.

An exemplary testing process for determining the benchmark force values F1-F4 by drying/testing various pre-weighed loads in the laundry drying appliance 10, 10′, 10″ is shown in FIGS. 15A-15C, which are a series of plots illustrating force and time curves for small, medium, and large load sizes of laundry in the drum. In FIGS. 15A-15C, force in Newtons (N) is shown on the vertical y-axis and time in seconds (s) is shown on the horizontal x-axis. FIG. 15A is a plot illustrating the force and time curve for a small load size of laundry in the drum 20, 20′. FIG. 15B is a plot illustrating the force and time curve for a medium load size of laundry in the drum 20, 20′. Finally, FIG. 15C is a plot illustrating the force and time curve for a large load size of laundry in the drum 20, 20′. The peaks shown in FIGS. 15A and 15B illustrate that for the small and medium load sizes, the laundry tumbles within the drum 20, 20′ where it is repetitively lifted and then falls away from the lifters 26 as the drum 20, 20′ rotates. Is tumbling action improves drying performance and reduces wrinkling. As can be seen in FIG. 15C, when a large load is placed in the drum 20, 20′, the laundry stops tumbling and we no longer see a series of peaks in the force and time curve. Under such a condition, drying performance is compromised and wrinkling is more common/significant.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A method of controlling a load volume of laundry in a laundry drying appliance, the method comprising the steps of: sensing a condition of the laundry drying appliance that is indicative of the load volume of laundry in the laundry drying appliance by receiving and processing one or more electrical signals from one or more sensors or electrical components positioned within the laundry drying appliance; determining the load volume of laundry in the laundry drying appliance based on the condition of the laundry drying appliance that is indicative of load volume; and determining if the load volume of laundry present in the laundry drying appliance exceeds a pre-determined maximum load volume value for a particular drying cycle of the laundry drying appliance.
 2. The method of claim 1, further comprising the step of: displaying an overload warning on a control panel of the laundry drying appliance if the pre-determined maximum load volume value is exceeded.
 3. The method of claim 1, further comprising the step of: highlighting and enabling a recommended cycle setting on a control panel of the laundry drying appliance if the pre-determined maximum load volume value is exceeded.
 4. The method of claim 1, further comprising the step of: terminating the drying cycle if the pre-determined maximum load volume value is exceeded.
 5. The method of claim 1, further comprising the step of: autonomously changing the drying cycle to a different drying cycle if the pre-determined maximum load volume value is exceeded.
 6. The method of claim 1, further comprising the steps of: processing one or more signals indicative of drum motor current draw to obtain a measured motor torque value; and comparing the measured motor torque value to one or more motor torque benchmark values.
 7. The method of claim 6, further comprising the step of: determining whether the measured motor torque value is greater than the one or more motor torque benchmark values to determine whether the load volume of laundry in the laundry drying appliance corresponds to a large load, a medium load, or a small load, or an overloaded condition.
 8. The method of claim 1, further comprising the steps of: processing one or more signals indicative of loaded drum weight or displacement to obtain a measured weight/displacement value; and comparing the measured weight/displacement value to one or more weight/displacement benchmark values.
 9. The method of claim 8, further comprising the step of: determining whether the measured weight/displacement value is greater than the one or more weight/displacement benchmark values to determine whether the load volume of laundry in the laundry drying appliance corresponds to a large load, a medium load, or a small load.
 10. The method of claim 1, further comprising the steps of: processing one or more signals indicative of exhaust temperature to obtain a measured exhaust temperature value; and comparing the measured exhaust temperature value to one or more exhaust temperature benchmark values.
 11. The method of claim 10, further comprising the step of: determining whether the measured exhaust temperature value is greater than the one or more exhaust temperature benchmark values to determine whether the load volume of laundry in the laundry drying appliance corresponds to a large load, a medium load, or a small load, or an overloaded condition.
 12. The method of claim 1, further comprising the steps of: processing one or more signals indicative of exhaust temperature and relative humidity to obtain a measured exhaust temperature value and a measured humidity value; calculating a calculated evaporation rate value from the measured exhaust temperature value and the measured humidity value; and comparing the calculated evaporation rate value to one or more evaporation rate benchmark values.
 13. The method of claim 12, further comprising the step of: determining whether the calculated evaporation rate value is greater than the one or more evaporation rate benchmark values to determine whether the load volume of laundry in the laundry drying appliance corresponds to a large load, a medium load, or a small load.
 14. The method of claim 1, further comprising the steps of: processing one or more signals indicative of a force on a drum component to obtain a measured force value; and comparing the measured force value to one or more benchmark force values.
 15. The method of claim 14, further comprising the step of: determining whether the measured force value is greater than the one or more benchmark force values to determine whether the load volume of laundry in the laundry drying appliance corresponds to a large load, a medium load, or a small load, or an overloaded condition.
 16. A laundry drying appliance, comprising: a cabinet with an opening enabling access inside the cabinet; a door coupled with the cabinet, the door covering the opening; a heating unit configured to heat air inside of the cabinet; a drum configured to receive laundry to be dried in the drying appliance; a control panel with a user interface that is configured to permit user selection of a desired drying cycle; and a controller integrated with or arranged in electronic communication with the control panel, wherein the controller is programmed to process one or more electrical signals that are received from one or more sensors or electrical components positioned within the cabinet to detect a condition of the laundry drying appliance that is indicative of load volume, wherein the controller is programmed to determine the load volume of laundry in the drum based on the condition of the laundry drying appliance that is indicative of load volume, and wherein the controller is programmed to determine if the load volume of laundry present in the drum exceeds a pre-determined maximum load volume value for the desired drying cycle.
 17. The laundry drying appliance of claim 16, wherein the control panel is configured to display an overload warning if the pre-determined maximum load volume value is exceeded.
 18. The laundry drying appliance of claim 16, wherein the control panel is configured to highlight a recommended cycle setting if the pre-determined maximum load volume value is exceeded.
 19. A washer/dryer combination appliance, comprising: a cabinet with an opening enabling access inside the cabinet; a door coupled with the cabinet, the door covering the opening; a heating unit configured heat air inside of the cabinet; a tub suspended within the cabinet; a drum rotatably supported within the tub, the drum configured to receive laundry to be washed and dried in the washer/dryer combination appliance; a control panel with a user interface that is configured to permit user selection of a desired drying cycle; and a controller integrated with or arranged in electronic communication with the control panel, wherein the controller is programmed to process one or more electrical signals that are received from one or more sensors or electrical components positioned within the cabinet to detect a condition of the laundry drying appliance that is indicative of load volume, wherein the controller is programmed to determine the load volume of laundry in the drum based on the condition of the laundry drying appliance that is indicative of load volume, and wherein the controller is programmed to determine if the load volume of laundry present in the drum exceeds a pre-determined maximum load volume value for the desired drying cycle.
 20. The washer/dryer combination appliance of claim 19, wherein the control panel is configured to display an overload warning or highlight a recommended cycle setting if the pre-determined maximum load volume value is exceeded. 